Along a Queens corridor busy with traffic, Mayor Bill de Blasio took a moment on Wednesday to stand at the memorial of an 8-year-old boy killed by a turning truck steps from his school.

Minutes later, before a news conference, parents who had similarly lost their children approached. He bent to listen. Cameras crackled; reporters craned in. “I’m so sorry,” he said softly to one parent. “We’re all united,” he told others.

Only two weeks into his administration, Mr. de Blasio set a sweeping goal on Wednesday: to bring the number of New Yorkers killed in traffic “literally” to zero, saying it would be “a central focus” of his administration.

Though the announcement was a modest step — the formation of an interagency working group — its timing and focus represented a major victory for pedestrian and cycling advocates who have long pressed the city to do more to stop traffic crashes.

“I see this through the eyes of a parent,” Mr. de Blasio said, speaking in the schoolyard of P.S. 152, near where the young boy, Noshat Nahian, was fatally struck in December by a tractor-trailer on Northern Boulevard and 61st Street.

Mr. de Blasio repeated a campaign pledge to adopt a Swedish traffic approach known as “vision zero” that views traffic deaths as preventable, often with street modifications and speed limit reductions.

More immediately, he said, drivers would see changes in the enforcement of traffic rules, including the ticketing of those caught on the city’s small number of speed cameras, who had previously been sent only warnings.

Appearing with the mayor, Police Commissioner William J. Bratton said that the Police Department was enlarging its Highway Division from about 220 to 270 officers, and that precinct commanders had been told to submit plans for pedestrian safety. He promised to beef up investigations of serious crashes to bolster potential prosecutions, which in the absence of drugs or alcohol can be difficult to pursue. Mr. Bratton cautioned that detectives must still find “criminality” to arrest drivers.

He also offered a statistic that appeared likely to be seized upon by those reluctant to support street configurations that slow down drivers. “Last year, pedestrian error — and I point this out — pedestrian error contributed to 73 percent of collisions,” Mr. Bratton said. “So while a lot of our focus is on drivers and speed, we also need to work more comprehensively on pedestrian education.”

Many of the changes discussed on Wednesday under the rubric of “vision zero” were in the works before Mr. de Blasio took office. The Police Department last year began conducting more-robust investigations of crashes that resulted in critical injuries. In June, after years of prodding from the Bloomberg administration, the State Legislature approved a program to install 20 speed-tracking cameras in school speed zones; the cameras would now be used to issue tickets.

In another echo of Mayor Michael R. Bloomberg, Mr. de Blasio called on the state on Wednesday to relinquish control of traffic camera policies to the city, which would allow the administration to expand red light and speed enforcement cameras on its own.

Mr. Bloomberg’s name did not come up in the news conference. Instead, Mr. de Blasio offered an indirect critique of his penchant for giving commissioners broad latitude to run their departments as they saw fit. Traffic safety advocates had complained that, under Mr. Bloomberg, they had the support of the transportation commissioner, Janette Sadik-Khan, but not the police commissioner, Raymond W. Kelly. Mr. de Blasio said those “silos” did not lead to the “kind of coordinated effort to take on this growing challenge.”

Mr. de Blasio stood at the podium flanked by Mr. Bratton; the incoming transportation commissioner, Polly Trottenberg; and officials from the Department of Health and Mental Hygiene and the Taxi and Limousine Commission — all of whom have a month to report back with detailed recommendations. Those are likely to include reducing the speed limit to 20 miles per hour on many streets, and physical changes of the sort employed broadly by Mr. Bloomberg, most notably around Times Square.

Mr. de Blasio has expressed ambivalence about the recent overhaul of the city’s streets. Asked at a debate in October about the pedestrian plazas on Broadway, he said that he was “a motorist,” adding that “the jury’s out” on the projects. He said on Wednesday that pedestrian plazas would be part of a separate “broad review.”

Mr. de Blasio has also referred to Ms. Sadik-Khan, Mr. Bloomberg’s transportation commissioner, as a “radical,” though his campaign platform included the construction of new bike lanes and the expansion of the city’s bike share program outside of Manhattan.

A version of this article appears in print on , on Page A23 of the New York edition with the headline: De Blasio Announces Steps to Reduce Traffic Deaths. Order Reprints | Today’s Paper | Subscribe